Image info

The view the original uncompressed image, click the file name hyperlink. To
download the original image, right click the hyperlink and choose "Save
Target As...". The original images are provided in BMP format, which is
a lossless format that doesn't use compression. As a result, these images can
be quite big and take a while to download. After download, you can open the
image in the AIC software and try some compression
algorithms yourself.

Images

Whole or part of the image, compressed using different algorithms:

Original image, 24 bpp

JPEG: 0.50 bpp
PSNR: 30.91db

JPEG-2000: 0.48 bpp
PSNR: 32.10 db

AIC: 0.50 bpp
PSNR: 31.79 db

Although only a part of the image is shown, the compression results apply to
the entire image. For every image, the compressed size is shown, in bits per
pixel, and the objective image quality expressed as the Peak Signal to Noise
Ratio (PSNR). This objective quality measure is a measure for how much the individual
image pixels differ from the original image. The higher the peak signal to noise
ratio, the higher the objective quality and the more the image resembles the
original. This does not necessarily mean that the subjective image quality is
also higher. For example, you may find that the JPEG-2000 image above has the
best quality because it pleases the eye the most. Others may find that this
image shows too much smoothing and blurring, as a result of which some details
get lost. Those people will usually find the AIC image more appealing.

Due to limitations of web browsers, all images are recompressed with JPEG at
the highest quality for display in the browser. However, since the highest quality
level is used, this has very little effect on the perceived quality of the images,
so the visual comparison remains valid.

Quality vs Compression chart

This chart shows the objective image quality against the compression ratio
and is helpful for comparing image codecs. It shows how the various codecs perform
at different bit rates:

The compression ratio is plotted at the bottom and the quality at the left.
The AIC codec is shown in green, the JPEG codec in red and the JPEG-2000 codec
in blue.
This chart shows that AIC performs close to JPEG-2000 at bit rates below 4 bits
per pixel, and outperforms JPEG-2000 at bit rates between 4 and 9 bits per pixel.
At higher bit rates, JPEG-2000 obviously takes the lead.